The perception and representation of object motion is of primary importance in both the processing of environmental information and in the execution of competent performance. This observation has motivated a systematic inquiry into the abilities that people display in perceiving, remembering, attending to, and understanding different kinds of motion. Research over the past three decades has made it clear that though our cognitive and perceptual faculties are exquisitely attuned to the translational motion of objects, these systems suffer dramatic and general failures when confronted with virtually any form of object rotation. In this proposal we explore the extent to which these failures are the result of attentional and memorial limitations in the processing of motion information. Attentional limitations in the analysis of motion are examined in Phase I using a multiple target visual search methodology. The ensemble of proposed experiments in Phase I are based on measurements of response time (RT) and accuracy to signal the presence/absence of one or more specified motion targets hidden in a field of motion distractors (e.g. a clockwise rotation among counter-clockwise rotations). The RT and accuracy data are then accounted for simultaneously using a capacity-limited, random walk model of search with key parameters that correspond to stimulus discriminability, attentional limitation, and decisional bias. This hybrid approach has the power to distinguish serial from parallel processes, and to provide continuous measures of attentional limitation during visual search for motion features. Memorial limitations in the perception of motion are examined in two separate lines of proposed work that probe explicit (phase II) and implicit (phase III) memory systems. Explicit memory for motion information is assessed using a standard "old"/"new" recognition paradigm in which people are shown a series of moving objects and are tested at a later time on their abilities to recognize various aspects of object motion. Implicit memory is examined using a novel temporal priming methodology that assesses processing speed contingent on prior motion experience. Patterns of facilitation and inhibition are used to decide what aspects of motion information receive implicit registration. [unreadable] [unreadable]